SM12 – Lock Entries Tips

If you check SM12 you may find some lock entries – this is not a problem. Locked entries are required in standard SAP processing. In most instances the entry will remain in SM12 for a few seconds milliseconds, however they could remain in SM12 for a lot longer depending on the logical unit of work.

Factors which can impact the entry in SM12:

• Sizing and performance of the enqueue server.
• Sizing and performance of the application server/number of available processing sessions. (indirectly related)
• Program logic being executed on the application server.

What you may not know is that there is a hidden menu path for SM12 analysis. To activate this menu path you can do the following:

Run SM12, then enter OK code “test”. You will now see the top menu path has included a new Menu Option labelled “Error Handling”.

This menu option has many parameters and test functions which you can use to analyse the enqueue and dequeue processes.

If you require advice on how to use this new functionality you can refer to OSS note 5424 which is the SM12 FAQ! Success!

Creating Database Table

Questionaire for Creating Database Tables

Compare two same database table contents

Sometimes we come up across a requirement to compare the contents of two database tables. For example to check if roles created in development have been successfully transferred to production or not. How do we do this???

SAP has provided a standard transaction code SCMP to compare contents of two database tables.

Table Buffering and Buffering types

Tables that are frequently read during production use, but only rarely modified, such as those containing configuration data, should be buffered on the application server. The access to data in a buffered table is 10-50 times faster than accessing data in a non-buffered table, being read from the database cache.  In the technical settings of a table in transaction SE11, you are able to turn on the table buffering and select the buffer type (fully buffered, generically buffered, or single record buffering).

In the following diagram it is depicted, how delivery class, data class, and buffering should be combined for (most of) the tables in your system.

Examples on how to read this diagram:

• delivery class C (customizing table) should not be combined with data class APPL1 (transactional data)
• a table that contains configuration data (APPL2), and which is assigned to delivery class S (system table), should be buffered
• a master data table (APPL0) with delivery class A (application table) should not be buffered, except if it has only a few entries (size category 0, or single record buffered with size category 0, 1, or 2)

Refer http://www.sdn.sap.com/irj/scn/weblogs?blog=/pub/wlg/25444 for more details.